Clocks are known for indicating real time and whether the next tide that is to occur will be high tide or low tide. A typical clock is one wherein the hands of the clock indicates real time, the clock face has high tide and low tide indicated thereon between 12 and 6 and between 6 and 12 while a third hand operated by the clock movement indicates whether the tide is operating at high tide or low tide but no indication is presented to indicate the time when high tide or low tide is to take place.
U.S. Pat. No. 3,982,104 discloses a time and tide calculating device for wrist watches and clocks that indicates the tides and the time of the tides which utilizes concentric tide and calendar disc means placed adjacent to a clock or watch face for indicative registration and cooperation with time telling devices whereby various arrangements of the tide and calendar disc show tide positions and the calendar data in registration with clock and watch faces that also includes information an time, data and whether the time is AM or PM. This arrangement is associated with the operation of the clock works or clock drive motor.